Network Access by a Reduced Capability User Equipment

ABSTRACT

A user equipment (UE) may attempt to access a base station of a network. The UE receives, from the base station of a wireless network, a broadcast including a system information block (SIB) identifying a plurality of random access channel (RACH) sub-bands of an uplink (UL) bandwidth and which of the plurality of RACH sub-bands includes physical random access channel (PRACH) resources. The base station selects one of the plurality of RACH sub-bands for a PRACH transmission and selects a preamble from the selected RACH sub-band and transmit the preamble to the base station to initiate a RACH procedure.

BACKGROUND

5G new radio (NR) wireless communications support a variety of differenttypes of user equipment (UEs). For example, in addition to mobilephones, 5G NR supports internet of things (IoT) devices, industrial IoT(IIoT) devices, wearable devices, etc. Some of these devices are knownas reduced capability (RedCap) UEs, which have varying wirelesscapabilities compared to other UEs.

SUMMARY

Some exemplary aspects are related to a user equipment (UE) having aprocessor and a transceiver communicatively connected to the processor.The processor is configured to perform operations that includereceiving, from a base station of a wireless network, a broadcastincluding a system information block (SIB) identifying a plurality ofrandom access channel (RACH) sub-bands of an uplink (UL) bandwidth andwhich of the plurality of RACH sub-bands includes physical random accesschannel (PRACH) resources, selecting one of the plurality of RACHsub-bands for a PRACH transmission and selecting a preamble from theselected RACH sub-band and transmit the preamble to the base station toinitiate a RACH procedure.

Other exemplary aspects are related to a baseband processor configuredto perform operations. The operations include receiving, from a basestation, a broadcast including a system information block (SIB)identifying a plurality of random access channel (RACH) sub-bands of anuplink (UL) bandwidth and which of the plurality of RACH sub-bandsincludes physical random access channel (PRACH) resources, selecting oneof the plurality of RACH sub-bands for a PRACH transmission andselecting a preamble from the selected RACH sub-band and transmit thepreamble to the base station to initiate a RACH procedure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an exemplary network arrangement according to variousexemplary aspects.

FIG. 2 shows an exemplary UE according to various exemplary aspects.

FIG. 3 shows an exemplary base station configured to establish aconnection with a user equipment according to various exemplary aspects.

FIG. 4 is a diagram illustrating random access channel (RACH) sub-bandsaccording to various exemplary aspects.

FIG. 5 is a diagram illustrating the allocation of physical RACH (PRACH)resources in RACH sub-bands according to various exemplary aspects.

FIG. 6 is a diagram illustrating PRACH formats that may be utilized forRACH sub-bands according to various exemplary aspects.

FIG. 7 is a flowchart illustrating a method of selecting a PRACHresource according to various exemplary aspects.

FIG. 8 is a diagram illustrating a determination of a message 2 (Msg2)and message 3 (Msg3) repetition according to various exemplary aspects.

FIG. 9 is a diagram illustrating a random access response according tovarious exemplary aspects.

DETAILED DESCRIPTION

The exemplary aspects may be further understood with reference to thefollowing description and the related appended drawings, wherein likeelements are provided with the same reference numerals. The exemplaryaspects describe manners of performing a network access procedure by areduced capability user equipment (RedCap UE).

The exemplary aspects are described with regard to a network thatincludes 5G new radio NR radio access technology (RAT). However, theexemplary aspects may be implemented in other types of networks usingthe principles described herein.

The exemplary aspects are also described with regard to a UE. However,the use of a UE is merely for illustrative purposes. The exemplaryaspects may be utilized with any electronic component that may establisha connection with a network and is configured with the hardware,software, and/or firmware to exchange information and data with thenetwork. Therefore, the UE as described herein is used to represent anyelectronic component.

As noted above, there are various UEs, each having differentcapabilities that connect to the 5G NR network. However, in a givenarea, it may not be beneficial to have different UEs having differentcapabilities camped on the same cell since reduced capability UEs mayutilize different parameters for wireless communications (e.g.,bandwidth parts, data rates, etc.) than other UEs (e.g., mobile phones,laptops, etc.), meaning the cell would need to tailor its communicationsto all types of UEs.

Prior to describing the exemplary aspects, several examples of RedCapUEs and their characteristics will be described. In a first example,devices in industrial settings such as temperature or humidity sensorsmay be connected industry devices. However, such devices are stationary,are not latency critical, and are fairly uncomplex with respect to theircapabilities and hardware. These devices typically do not require thelow latency data exchange provided by ultra reliable low latencycommunication (URLLC) or IIoT. It is also expected that these deviceswill operate in the field for many years with little to no maintenance,including battery replacement. Thus, power saving operations may becritical for these types of devices.

Another example of RedCap type devices with capabilities that differfrom other UEs are surveillance devices (e.g., cameras). These devicesare similar to the devices in the first example in that they aretypically stationary and do not have stringent latency requirements.However, they may differ from the first example because these devicesmay be connected to a permanent power supply (although not required) andmay have much higher upload data rates than many other UEs because of,for example, the video upload feeds they are providing.

Yet another example of RedCap type devices with different capabilitiesthan many other UEs are wearable devices. Unlike the above examples,wearables typically have similar mobility to mobile phones andoperations related to the same types of applications that are executableon mobile phones. However, because of the smaller form factor resultingin smaller batteries, these devices have a more stringent power savingrequirement than mobile phones.

These examples of different types of UEs are by no means an exhaustivelist of 5G-capable devices, but are provided as an example of thevarying capabilities of different UEs that are connected to the 5G NRwireless network at any given time. Devices that are considered RedCapdevices may be limited in the bandwidth provided to them either bystandards (e.g., 3GPP standards) or by individual network providers. Asa result of this decreased bandwidth, coverage area may be sacrificed.Although slot aggregation or repetition may be used to compensate forthis loss of coverage, such options are not supported prior to the radioresource control (RRC) configuration of the UE. As such, a random accesschannel (RACH) process of attaching a RedCap UE to a cell is necessary.

According to some exemplary aspects, the 5G NR network may divide thebandwidth part of a component carrier (CC) into smaller bandwidthsub-bands and distribute the physical RACH (PRACH) resources for theRACH procedure among one or more of the sub-bands. As a result, theoverhead resources allocated to serve RedCap devices are advantageouslyreduced while ensuring that these RedCap devices can still successfullyattach to a cell.

FIG. 1 shows an exemplary network arrangement 100 according to variousexemplary aspects. The exemplary network arrangement 100 includes a UE110. It should be noted that any number of UEs may be used in thenetwork arrangement 100. Those skilled in the art will understand thatthe UE 110 may alternatively be any type of electronic component that isconfigured to communicate via a network, e.g., mobile phones, tabletcomputers, desktop computers, smartphones, phablets, embedded devices,wearables, Internet of Things (IoT) devices, etc. It should also beunderstood that an actual network arrangement may include any number ofUEs being used by any number of users. Thus, the example of a single UE110 is merely provided for illustrative purposes.

The UE 110 may be configured to communicate with one or more networks.In the example of the network configuration 100, the networks with whichthe UE 110 may wirelessly communicate are a 5G New Radio (NR) radioaccess network (5G NR-RAN) 120, an LTE radio access network (LTE-RAN)122 and a wireless local access network (WLAN) 124. However, it shouldbe understood that the UE 110 may also communicate with other types ofnetworks and the UE 110 may also communicate with networks over a wiredconnection. Therefore, the UE 110 may include a 5G NR chipset tocommunicate with the 5G NR-RAN 120, an LTE chipset to communicate withthe LTE-RAN 122 and an ISM chipset to communicate with the WLAN 124.

The 5G NR-RAN 120 and the LTE-RAN 122 may be portions of cellularnetworks that may be deployed by cellular providers (e.g., Verizon,AT&T, Sprint, T-Mobile, etc.). These networks 120, 122 may include, forexample, cells or base stations (Node Bs, eNodeBs, HeNBs, eNBS, gNBs,gNodeBs, macrocells, microcells, small cells, femtocells, etc.) that areconfigured to send and receive traffic from UE that are equipped withthe appropriate cellular chip set. The WLAN 124 may include any type ofwireless local area network (WiFi, Hot Spot, IEEE 802.11x networks,etc.).

The UE 110 may connect to the 5G NR-RAN 120 via the gNB 120A and/or thegNB 120B. During operation, the UE 110 may be within range of aplurality of gNBs. Thus, either simultaneously or alternatively, the UE110 may connect to the 5G NR-RAN 120 via the gNBs 120A and 120B.Further, the UE 110 may communicate with the eNB 122A of the LTE-RAN 122to transmit and receive control information used for downlink and/oruplink synchronization with respect to the 5G NR-RAN 120 connection.

Those skilled in the art will understand that any association proceduremay be performed for the UE 110 to connect to the 5G NR-RAN 120. Forexample, as discussed above, the 5G NR-RAN 120 may be associated with aparticular cellular provider where the UE 110 and/or the user thereofhas a contract and credential information (e.g., stored on a SIM card).Upon detecting the presence of the 5G NR-RAN 120, the UE 110 maytransmit the corresponding credential information to associate with the5G NR-RAN 120. More specifically, the UE 110 may associate with aspecific base station (e.g., the gNB 120A of the 5G NR-RAN 120).

In addition to the networks 120, 122 and 124 the network arrangement 100also includes a cellular core network 130, the Internet 140, an IPMultimedia Subsystem (IMS) 150, and a network services backbone 160. Thecellular core network 130 may be considered to be the interconnected setof components that manages the operation and traffic of the cellularnetwork, e.g. the 5GC for NR. The cellular core network 130 also managesthe traffic that flows between the cellular network and the Internet140.

The IMS 150 may be generally described as an architecture for deliveringmultimedia services to the UE 110 using the IP protocol. The IMS 150 maycommunicate with the cellular core network 130 and the Internet 140 toprovide the multimedia services to the UE 110. The network servicesbackbone 160 is in communication either directly or indirectly with theInternet 140 and the cellular core network 130. The network servicesbackbone 160 may be generally described as a set of components (e.g.,servers, network storage arrangements, etc.) that implement a suite ofservices that may be used to extend the functionalities of the UE 110 incommunication with the various networks.

FIG. 2 shows an exemplary UE 110 according to various exemplary aspects.The UE 110 will be described with regard to the network arrangement 100of FIG. 1. For purposes of this discussion, the UE 110 may be consideredto be a reduced capability (RedCap) UE. However, it should be noted thatthe UE 110 may represent any electronic device and may include aprocessor 205, a memory arrangement 210, a display device 215, aninput/output (I/O) device 220, a transceiver 225 and other components230. The other components 230 may include, for example, an audio inputdevice, an audio output device, a battery that provides a limited powersupply, a data acquisition device, ports to electrically connect the UE110 to other electronic devices, one or more antenna panels, etc. Forexample, the UE 110 may be coupled to an industrial device via one ormore ports.

The processor 205 may be configured to execute a plurality of engines ofthe UE 110. For example, the engines may include a RACH managementengine 235. As will be described in more detail below, the RACHmanagement engine 235 may perform various operations related to RACHprocedure such as, for example, processing system information block 1(SIB1) to determine the sub-bands carrying PRACH resources, selectingone of the sub-bands for PRACH transmission, etc.

The above referenced engine being an application (e.g., a program)executed by the processor 205 is only exemplary. The functionalityassociated with the engine may also be represented as a separateincorporated component of the UE 110 or may be a modular componentcoupled to the UE 110, e.g., an integrated circuit with or withoutfirmware. For example, the integrated circuit may include inputcircuitry to receive signals and processing circuitry to process thesignals and other information. The engines may also be embodied as oneapplication or separate applications. In addition, in some UE, thefunctionality described for the processor 205 is split among two or moreprocessors such as a baseband processor and an applications processor.The exemplary aspects may be implemented in any of these or otherconfigurations of a UE.

The memory arrangement 210 may be a hardware component configured tostore data related to operations performed by the UE 110. The displaydevice 215 may be a hardware component configured to show data to a userwhile the I/O device 220 may be a hardware component that enables theuser to enter inputs. The display device 215 and the I/O device 220 maybe separate components or integrated together such as a touchscreen. Thetransceiver 225 may be a hardware component configured to establish aconnection with the 5G NR-RAN 120, the LTE-RAN 122, the WLAN 124, etc.Accordingly, the transceiver 225 may operate on a variety of differentfrequencies or channels (e.g., set of consecutive frequencies).

FIG. 3 shows an exemplary network cell, in this case gNB 120A, accordingto various exemplary aspects. The gNB 120A may represent any access nodeof the 5G NR network through which the UEs 110 may establish aconnection. The gNB 120A illustrated in FIG. 3 may also represent thegNB 120B.

The gNB 120A may include a processor 305, a memory arrangement 310, aninput/output (I/O) device 320, a transceiver 325, and other components330. The other components 330 may include, for example, a power supply,a data acquisition device, ports to electrically connect the gNB 120A toother electronic devices, etc.

The processor 305 may be configured to execute a plurality of engines ofthe gNB 120A. For example, the engines may include a RACH managementengine 335 for performing operations including managing RACH proceduresof RedCap UEs to attach to the gNB 120A. Examples of managing RACHprocedures will be described in greater detail below.

The above noted engine being an application (e.g., a program) executedby the processor 305 is only exemplary. The functionality associatedwith the engines may also be represented as a separate incorporatedcomponent of the gNB 120A or may be a modular component coupled to thegNB 120A, e.g., an integrated circuit with or without firmware. Forexample, the integrated circuit may include input circuitry to receivesignals and processing circuitry to process the signals and otherinformation. In addition, in some gNBs, the functionality described forthe processor 305 is split among a plurality of processors (e.g., abaseband processor, an applications processor, etc.). The exemplaryaspects may be implemented in any of these or other configurations of agNB.

The memory 310 may be a hardware component configured to store datarelated to operations performed by the UEs 110, 112. The I/O device 320may be a hardware component or ports that enable a user to interact withthe gNB 120A. The transceiver 325 may be a hardware component configuredto exchange data with the UE 110 and any other UE in the system 100. Thetransceiver 325 may operate on a variety of different frequencies orchannels (e.g., set of consecutive frequencies). Therefore, thetransceiver 325 may include one or more components (e.g., radios) toenable the data exchange with the various networks and UEs.

FIG. 4 is a diagram illustrating random access channel (RACH) sub-bands402 according to various exemplary aspects. The set of RACH sub-bands402 for RedCap RACH procedures may span either a subset or the entiredownlink (DL) component carrier (CC) bandwidth (N_(CC) ^(size))configured for a given cell. The exemplary sub-band configurationillustrated in FIG. 4 includes four sub-bands (0, 1, 2, and 3), eachhaving N_(subband) ^(size) resource blocks. The value of N_(subband)^(size) may be determined in various ways. For example, in some aspects,N_(subband) ^(size) may be configured by the SIB1 received by the RedCapUE 110. For example, the value N_(subband) ^(size) may be broadcast inthe system information of the SIB1 by the gNB 120A. In some aspects, thevalue of N_(subband) ^(size) may alternatively be a function of the DLCC bandwidth. In some aspects, the value of N_(subband) ^(size) mayalternatively be set by standards (e.g., 3GPP standards) and may bebased on the bandwidth capability of the RedCap UE 110 (e.g., 10 MHz or20 MHz for frequency range 1; and 50 MHz or 100 MHz for frequency range2) and a subcarrier spacing “u”. For example, the value of N_(subband)^(size,u) may be 100/50/25 for a subcarrier spacing “u” of 0, 1, 2 or136/68 for a subcarrier spacing “u” of 2, 3, 4.

FIG. 5 is a diagram illustrating the allocation of physical RACH (PRACH)resources 504 in RACH sub-bands 502 according to various exemplaryaspects. In some aspects, the set of RACH sub-bands 502 that include thePRACH resources 504 may be identified by the rach-ConfigCommoninformation element (IE) in the SIB1 broadcast by the gNB 122A. Oneexemplary abstract syntax notation one (ASN.1) signaling that indicatesa set of RACH sub-bands that include PRACH resources may beRACHSubBandList::=BITSTRING(SIZE(maxNrofRACHSubBands)), where“BITSTRING” is a binary string in which a value of 0 indicates that thecorresponding sub-band does not include PRACH resources and a value of 1indicates that the corresponding sub-bands includes PRACH resources. Inthe example illustrated in FIG. 5, the BITSTRING would have a value of01110, indicating that the middle three sub-bands (sub-band index 1, 2,and 3) of the five sub-bands 502 include the PRACH resources 504.

In some aspects, various methods may be used to indicate the frequencydomain starting position of the respective PRACH resource 504 in eachRACH sub-band 502. For example, in some aspects, a single offset value500 (n_(RA) ^(start)) is configured by RRC signaling relative to thestarting physical resource block (PRB) of each associated RACH sub-band502 and is used to determine the PRACH resource location in eachsub-band. For example, the respective offsets 510 (n_(RA) ^(start,1)),520 (n_(RA) ^(start,2))), and 530 (n_(RA) ^(start,3)) would all have thesame value (e.g., n_(RA) ^(start)). In some aspects, a separate offsetvalue n_(RA) ^(start,i) may alternatively be utilized for eachrespective sub-band. For example, the respective offsets 510 (n_(RA)^(start,1)), 520 (n_(RA) ^(start,2)), and 530 (n_(RA) ^(start,3)) mayeach have a different value. In some aspects, separate offsets 550(n_(RA) ^(start,1)), 570 (n_(RA) ^(start,2)), and 580 (n_(RA)^(start,3)) may alternatively be configured with respect to a commonreference point such as, for example, the starting resource block (RB)for the UL BWP. Having different offset values may allow the gNB 120A totransmit other UL transmission resources during the offset.

FIG. 6 is a diagram illustrating PRACH formats 600 and 610 that may beutilized for RACH sub-bands according to various exemplary aspects. Insome aspects, different PRACH formats may be configured for PRACHresources in different RACH sub-bands. In such an aspect, a separateprach-ConfigurationIndex IE may utilized for each sub-band to identifythe PRACH format of that corresponding sub-band. Utilization ofdifferent PRACH formats advantageously allow for the efficientutilization of network resources since different PRACH formats havecorresponding different coverage properties. For example, the maximumcell ranges associated with PRACH format A3 (6 symbols) and PRACH formatB4 (12 symbols) can reach up to 3,516 meters and 3,867 meters,respectively, given a sub-carrier spacing of 15 kHz, which can be usedby UEs at the cell edge to improve initial access performance. On theother hand, for UEs at the center of the cell, PRACH format A1/B1 with 2symbols may suffice to meet the initial access performance requirements.

In some aspects, the PRACH format may be based on the location of theRedCap UE 110 within the cell (e.g., how far it is from the gNB). Thegreater the number of symbols in the PRACH resource, the larger thenumber of repetitions (e.g., 6 symbols=6 repetitions). Greaterrepetitions ensure improved carrier performance by ensuring thatcommunications from the RedCap UE 1110 successfully reach the gNB 120Aand the RACH procedure is successfully completed. FIG. 6 illustrates anexample of different PRACH formats for two RA sub-bands 600 and 610 byusing a separate prach-ConfigurationIndex IE for each sub-band.

FIG. 7 is a flowchart illustrating a method 700 of selecting a PRACHresource according to various exemplary aspects. At 705, the RedCap UE110 obtains the RACH sub-band configuration and theprach-ConfigurationIndex for its serving cell. This information isindicated in the SIB that the RedCap UE 110 receives from the gNB 120Aand informs the UE which RACH sub-bands include the PRACH resources, thePRACH format(s), and the periodicity of the corresponding RACH sub-bandwith the PRACH resource.

In some aspects, in addition to the RACH sub-band configuration and theprach-ConfigurationIndex, the SIB1 may include additional configurationinformation. In some aspects, this additional information may beprovided separately on a per RACH sub-band basis. In some aspects, suchadditional information may include one or more of (1) a random accessresponse (RAR) window size (ra-ResponseWindowSize), (2) a power-rampingfactor, (3) an initial preamble power, (4) a maximum number of message 3(Msg3) hybrid automatic repeat request (HARQ) transmissions, (5) acontention resolution timer (mac-ContentionResolutionTimer), (6) thenumber of attempts per RACH sub-band, and/or (7) the number ofMsg2/Msg3/Msg4 repetitions. With respect to the RAR window size, in someaspects, the window size may be a function of the RACH repetition level.For example, the window size may be based on the PRACH format selectedfor each respective RACH sub-band.

With respect to the number of Msg2/Msg3/Msg4 repetitions, the repetitionnumber may be based on the PRACH format. For example, in the case ofPRACH format A3 (e.g., exemplary PRACH format 600), which includes 6symbols, the repetition number may correspond to the number of symbols(6 repetitions).

In some aspects, the number of repetitions for each message(Msg2/Msg3/Msg4) may alternatively be defined as K=K_(PRACH)+Δ, where Kis the number of symbols in the PRACH format and Δ is a constantconfigured in the SIB transmission. It should be noted that a differentΔ value may be configured to Msg2/Msg4 than for Msg3. FIG. 8 is adiagram illustrating a determination of a message 2 (Msg2) and message 3(Msg3) repetition according to various exemplary aspects. FIG. 8 assumesthat the Δ value configured is 0. As such, given a PRACH format 802having 3 symbols, the PDCCH repetition scheduling of Msg2 804, the Msg2repetition 806, and the Msg3 repetition 808 are all equal to 3. However,as noted above, these repetition value may be different depending on theconfigured Δ value.

In some aspects, the number of Msg3 repetitions may alternatively beexplicitly indicated in Msg2 (RAR). FIG. 9 is a diagram illustrating aRAR 900 according to various exemplary aspects. In such an aspect, thenumber of Msg3 repetitions may be determined by the R value 902 of theRAR. In some aspects, the R value 902 may indicate one of two possiblerepetition values. In some aspects, a predetermined number of bits of anuplink (UL) grant 904 in the RAR may alternatively indicate one of a setof predetermined repetition values. In aspects in which the number ofMsg3 repetitions are configured by Msg2 as just explained, the number ofMsg2 and Msg4 repetitions may be based on the PRACH format as explainedabove.

In some aspects, the transmission power for PRACH and Msg3 may beadjusted based on the corresponding repetition of the selected PRACHformat. In such an aspect, abrupt jumps in the accumulated power levelsdue to the repetition level ramping are advantageously avoided and,therefore, reduce the impact of near-far effects.

Returning to FIG. 7, in addition to the configuration informationprovided at 705 discussed above, in some aspects, a list of referencesignal received power (RSRP) thresholds may also be configured in theSIB as “RSRP-ThresholdsPrachInfoList-r17::=SEQUENCE (SIZE(1 . . . N)) OFRSRP-Range.” Up to N RSRP thresholds may be configured. As will bedescribed below, the RSRP thresholds will be utilized in the selectionof the RACH sub-band at 710.

At 710, the RedCap UE 110 selects a RACH sub-band for PRACH transmissionbased on a DL RSRP measurement by the RedCap UE 110. The RedCap UE 110estimates the path-loss by averaging measurements of the RSRP based on areference signal such as, for example, the SIB or a channel stateinformation (CSI) reference signal. The measured RSRP is then comparedwith the RSRP thresholds configured in the SIB received at 705 to selectthe RACH sub-band. In some aspects, the RedCap UE 110 measures the RSRPof the detected strongest synchronization signal block (SSB). If themeasured RSRP is less than the RSRP threshold of enhanced coverage level(PRACH format) N and UE supports (e.g., is capable of) enhanced coveragelevel N, then the UE selects the RACH sub-band that is associated withcoverage level N at 710. If, however, multiple RACH sub-bands providePRACH resources for the same coverage level, the Redcap UE 110 randomlyselects one of these sub-bands. In some aspects, different selectionprobabilities may alternatively be configured for each RACH sub-band.

At 715, the RedCap UE 110 randomly selects one preamble from theselected RACH sub-band and transmits it to the gNB 122A to initiate theRACH procedure. In some aspects, for each RACH Sub-band, the RedCap UE110 applies power ramping for all PRACH repetition levels, except forthe highest repetition level. In some aspects, when RedCap UE 110receives the RAR (Msg2) but fails contention resolution, the UE uses itscurrent repetition level until the maximum number of attempts for thatlevel has been reached. That is, if the UE fails contention resolution(Msg3 collision), then the UE can select another PRACH format and usethe current repetition level until the max number of attempts arereached. However, randomly selecting other PRACH formats every time theUE fails contention resolution a waste of resources since there is noguarantee that the UE will succeed using those PRACH formats.

Those skilled in the art will understand that the above-describedexemplary aspects may be implemented in any suitable software orhardware configuration or combination thereof. An exemplary hardwareplatform for implementing the exemplary aspects may include, forexample, an Intel x86 based platform with compatible operating system, aWindows OS, a Mac platform and MAC OS, a mobile device having anoperating system such as iOS, Android, etc. In a further example, theexemplary aspects of the above described method may be embodied as aprogram containing lines of code stored on a non-transitory computerreadable storage medium that, when compiled, may be executed on aprocessor or microprocessor.

Although this application described various aspects each havingdifferent features in various combinations, those skilled in the artwill understand that any of the features of one aspect may be combinedwith the features of the other aspects in any manner not specificallydisclaimed or which is not functionally or logically inconsistent withthe operation of the device or the stated functions of the disclosedaspects.

It is well understood that the use of personally identifiableinformation should follow privacy policies and practices that aregenerally recognized as meeting or exceeding industry or governmentalrequirements for maintaining the privacy of users. In particular,personally identifiable information data should be managed and handledso as to minimize risks of unintentional or unauthorized access or use,and the nature of authorized use should be clearly indicated to users.

It will be apparent to those skilled in the art that variousmodifications may be made in the present disclosure, without departingfrom the spirit or the scope of the disclosure. Thus, it is intendedthat the present disclosure cover modifications and variations of thisdisclosure provided they come within the scope of the appended claimsand their equivalent.

1. A user equipment (UE), comprising: a processor configured to performoperations comprising: receiving, from a base station of a wirelessnetwork, a broadcast including a system information block (SIB)identifying a plurality of random access channel (RACH) sub-bands of anuplink (UL) bandwidth and which of the plurality of RACH sub-bandsincludes physical random access channel (PRACH) resources; selecting oneof the plurality of RACH sub-bands for a PRACH transmission; andselecting a preamble from the selected RACH sub-band and transmit thepreamble to the base station to initiate a RACH procedure; and atransceiver communicatively connected to the processor.
 2. The UE ofclaim 1, wherein the SIB further includes one or more offset valuesindicating a starting position of each PRACH resource within acorresponding one of the plurality of RACH sub-bands that includes thePRACH resources.
 3. The UE of claim 2, wherein the one or more offsetvalues is a single value.
 4. The UE of claim 2, wherein the one or moreoffset values includes a plurality of values corresponding to RACHsub-bands that include the PRACH resources.
 5. The UE of claim 4,wherein the separate values are with respect to a common reference pointin the UL bandwidth.
 6. The UE of claim 1, wherein the SIB furtherincludes a PRACH format configuration.
 7. The UE of claim 6, wherein thePRACH format configuration is different for each of the PRACH resources.8. The UE of claim 6, wherein the SIB further includes a repetitionnumber configuration for a number of message 2 (Msg2) repetitions, anumber of message 3 (Msg3) repetitions, and a number of message 4 (Msg4)repetitions.
 9. The UE of claim 8, wherein the number of Msg2, Msg3, andMsg4 repetitions is equal to the sum of (1) the number of symbolscorresponding to the PRACH format of the corresponding RACH sub-band and(2) a constant configured by the SIB.
 10. The UE of claim 8, wherein thenumber of Msg3 repetitions is explicitly indicated in a random accessresponse (RAR) of Msg2.
 11. The UE of claim 10, wherein one of an Rheader field of the RAR indicates the number of Msg3 repetitions or apredetermined number of bits of a UL grant in the RAR indicates thenumber of Msg3 repetitions.
 12. (canceled)
 13. The UE of claim 1,wherein the SIB further includes a list of reference signal receivedpower (RSRP) threshold values.
 14. The UE of claim 13, wherein, toselect the one of the plurality of RACH sub-bands for the PRACHtransmission, the operations further comprising: measuring an RSRP of areference signal; and comparing the measured RSRP with the RSRPthreshold values.
 15. A baseband processor configured to performoperations comprising: receiving, from a base station, a broadcastincluding a system information block (SIB) identifying a plurality ofrandom access channel (RACH) sub-bands of an uplink (UL) bandwidth andwhich of the plurality of RACH sub-bands includes physical random accesschannel (PRACH) resources; selecting one of the plurality of RACHsub-bands for a PRACH transmission; and selecting a preamble from theselected RACH sub-band and transmit the preamble to the base station toinitiate a RACH procedure.
 16. The baseband processor of claim 15,wherein the SIB further includes one or more offset values indicating astarting position of each PRACH resource within a corresponding one ofthe plurality of RACH sub-bands that includes the PRACH resources.17-19. (canceled)
 20. The baseband processor of claim 15, wherein theSIB further includes a PRACH format configuration.
 21. The basebandprocessor of claim 20, wherein the PRACH Format configuration isdifferent for each of the PRACH resources.
 22. The baseband processor ofclaim 20, wherein the SIB further includes a repetition numberconfiguration for a number of message 2 (Msg2) repetitions, a number ofmessage 3 (Msg3) repetitions, and a number of message 4 (Msg4)repetitions.
 23. The baseband processor of claim 22, wherein the numberof Msg2, Msg3, and Msg4 repetitions is equal to the sum of (1) thenumber of symbols corresponding to the PRACH format of the correspondingRACH sub-band and (2) a constant configured by the SIB.
 24. The basebandprocessor of claim 22, wherein the number of Msg3 repetitions isexplicitly indicated in a random access response (RAR) of Msg2. 25-28.(canceled)